Transcript for Trump, Biden face off in final presidential debate with added rules
In a last-ditch effort to appeal to a large audience of American voters, president trump and former vice president Joe Biden began with what some would consider a traditional debate. We're about to go into a dark winter. And he has no clear plan and there's no prospect that there's going to be a vaccine available for the majority of the American people before the middle of next year. President trump, your reaction? He says you have no plan. I don't think we're going to have a dark winter at all. We're opening up our country. We've learned and studied and understand the disease, which we didn't at the beginning. Reporter: Their policy differences on the pandemic front and center. That's what's happening, and he wants to close down, he'll close down the country if one person in our -- in our massive bureaucracy says we should close it down. Vice president Biden? Simply not true. We ought to be able to walk and chew gum at the same time. We ought to be able to safely open, but they need resources to open. You need to be able to, for example, if you're going to open a business, have social distancing within the business. Reporter: It was quite the contrast to the first debate. Why wouldn't you answer that question? Because the question is -- Reporter: The president initially restrained tonight. I take full responsibility. It's not my fault that it came here, it's China's fault. And you know what it's not Joe's fault that it came here either, it's China's fault. They kept it from going into the rest of China, for the most part, but they didn't keep it from coming out to the world, including Europe and ourselves. Reporter: Defending his response to the virus. We closed up the greatest economy in the world in order to fight this horrible disease that came from China. It's a worldwide pandemic. It's all over the world. You see the spikes in Europe and many other places right now. I say we're learning to live with it. We have no choice. We can't lock ourselves up in a basement like Joe does. Reporter: Biden in turn hammering the president. 220,000 Americans dead. You hear nothing else I say tonight, hear this. Anyone who's responsible for not taking control, in fact, not saying -- I take no responsibility initially, anyone responsible for that many deaths should not remain president of America. Reporter: The battle on the airwaves, on social media, on the ground. Biden continues to hold a consistent lead in polls nationally as well as in many must-win states. At least 47 million Americans have already voted, demonstrating intense interest in the outcome this year. Even astronaut Kate Rubin voting from outer space today. Since his recovery from covid, the president has been holding rallies in contested states every day, despite scientists' warnings against large gatherings. We are going to keep on working. We are going to keep on fighting. We are going to keep on winning, winning, winning. Reporter: While Biden, by comparison, stayed off the trail, instead unleashing the Democrats' strongest not so secret weapon, former president Obama. His mission, to make sure minorities and young voters who sat out the 2016 election don't stay home this time. In the end, Pennsylvania, that's what voting's about, making things better. Not making things perfect, but putting us on track so that a generation from now, we can look back and say, things got better starting now. Reporter: Looming over tonight's debate, the almost predictable news from the intelligence community that Iran and Russia are engaging in election interference, sending intimidating emails threatening vote percent they don't vote for president trump. Now we learn that Iran is involved. They will pay a price if I'm they're interfering with American sovereignty. Reporter: President trump arguing that there is no way Russia wants him to win. There has been nobody tougher to Russia, between the sanctions -- nobody tougher than me on Russia. Reporter: Then pivoting to attack Joe Biden's son hunter and his business dealings abroad in Ukraine. I hear they paid him $183,000 a month, listen to this, 183, gave him a $3 million up-front payment -- All right, I'm going to let the vice president respond quickly -- No basis for that. Everybody investigated that. No one said anything he did was wrong in Ukraine. Reporter: President trump launching another attack using unverified accusations about the Biden family's business dealings. Pier this stuff is true about Russia, Ukraine, China, other countries, Iraq. If this is true, then he's a corrupt politician. There are 50 former national intelligence folks who said that what he's accusing me of is a Russian plant. Both parties say what he's saying is a bunch of garbage. Reporter: NBC news' Kristin Welker questioned the president about a recent "New York Times" report claiming the president maintains a bank account in China. I have many bank accounts, and they're all listed, and they're all over the place. I mean, I was a businessman doing business. The bank account was in 2013. That's what it was. It was opened in -- it was closed in 2015, I believe. Reporter: After months of unrest and calls for racial justice, both men asked if they understand the lived experience of black and brown Americans. Nobody has done more for the black community than Donald Trump. And if you look, with the exception of Abraham Lincoln, possible exception, but the exception of Abraham Lincoln, nobody has done what I've done. Abraham Lincoln here is one of the most racist presidents we've had in modern history. He pours fuel on every single racist fire, every single one. This guy has a dog whistle big as a fog horn. Reporter: On one of the most crucial issues for voters, health care, president trump declining to provide any specifics about his plans for replacing Obamacare, a 2016 campaign promise he has yet to We'll always protect people with pre-existing. So I'd like to terminate Obamacare, come up with a brand-new beautiful health care -- Reporter: Biden saying he'd expand Obamacare with a public option, calling it Biden care. Public option is an option that says that, if you, in fact, do not have the wherewithal to be -- if you qualify for medicaid and you do not have the wherewithal in your state to get medicaid, you're automatically enrolled, providing competition for insurance companies. Reporter: Biden going on offense, challenging the president on recent reports that the government cannot find the parents of 545 children still separated at the border under president trump's immigration policies. Do you have a plan to reunite the kids? Yes, we're working on it very -- we're trying very hard. But a lot of these kids come out without the parents. They come over through cartels and through coyotes and through gangs. Coyotes didn't bring them over, their parents were with them. They got separated from their parents and it makes us a laughingstock and violates every notion of who we are as a nation. They are so well taken care of. They're in facilities that were so clean. Reporter: Each candidate offered the opportunity to give a unifying message, which each attempted but then reverted to We are on the road to success. But I'm cutting taxes, and he wants to raise everybody's taxes, and he wants to put new regulations on everything. He will kill it. If he gets in, you will have a depression the likes of which you've never seen. Your 401(k)s will go to hell. And it will be a very, very sad day for this country. I will say, I'll be an American president. I'll represent all of you, whether you voted for me or against me. What is on the ballot here is the character of this country. Decency, honor, respect, treating people with dignity, making sure that everyone has an even chance. And I'm going to make sure you get that. You haven't been getting it the last four years. Reporter: With only 12 days to go, they'll no doubt be back at it tomorrow.
This transcript has been automatically generated and may not be 100% accurate.